 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.text.edits;

 import java.util.List ;

 import org.eclipse.core.runtime.Assert;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;

 /**
  * A copy target edit denotes the target of a copy operation. Copy
  * target edits are only valid inside an edit tree if they have a
  * corresponding source edit. Furthermore a target edit can't
  * can't be a direct or indirect child of the associated source edit.
  * Violating one of two requirements will result in a <code>
  * MalformedTreeException</code> when executing the edit tree.
  * <p>
  * Copy target edits can't be used as a parent for other edits.
  * Trying to add an edit to a copy target edit results in a <code>
  * MalformedTreeException</code> as well.
  *
  * @see org.eclipse.text.edits.CopySourceEdit
  *
  * @since 3.0
  */
 public final class CopyTargetEdit extends TextEdit {

     private CopySourceEdit fSource;

     /**
      * Constructs a new copy target edit
      *
      * @param offset the edit's offset
      */
     public CopyTargetEdit(int offset) {
         super(offset, 0);
     }

     /**
      * Constructs an new copy target edit
      *
      * @param offset the edit's offset
      * @param source the corresponding source edit
      */
     public CopyTargetEdit(int offset, CopySourceEdit source) {
         this(offset);
         setSourceEdit(source);
     }

     /*
      * Copy constructor
      */
     private CopyTargetEdit(CopyTargetEdit other) {
         super(other);
     }

     /**
      * Returns the associated source edit or <code>null</code>
      * if no source edit is associated yet.
      *
      * @return the source edit or <code>null</code>
      */
     public CopySourceEdit getSourceEdit() {
         return fSource;
     }

     /**
      * Sets the source edit.
      *
      * @param edit the source edit
      *
      * @exception MalformedTreeException is thrown if the target edit
      * is a direct or indirect child of the source edit
      */
     public void setSourceEdit(CopySourceEdit edit) throws MalformedTreeException {
         Assert.isNotNull(edit);
         if (fSource != edit) {
             fSource= edit;
             fSource.setTargetEdit(this);
             TextEdit parent= getParent();
             while (parent != null) {
                 if (parent == fSource)
                     throw new MalformedTreeException(parent, this, TextEditMessages.getString("CopyTargetEdit.wrong_parent")); //$NON-NLS-1$
 parent= parent.getParent();
             }
         }
     }

     /*
      * @see TextEdit#doCopy
      */
     protected TextEdit doCopy() {
         return new CopyTargetEdit(this);
     }

     /*
      * @see TextEdit#postProcessCopy
      */
     protected void postProcessCopy(TextEditCopier copier) {
         if (fSource != null) {
             CopyTargetEdit target= (CopyTargetEdit)copier.getCopy(this);
             CopySourceEdit source= (CopySourceEdit)copier.getCopy(fSource);
             if (target != null && source != null)
                 target.setSourceEdit(source);
         }
     }

     /*
      * @see TextEdit#accept0
      */
     protected void accept0(TextEditVisitor visitor) {
         boolean visitChildren= visitor.visit(this);
         if (visitChildren) {
             acceptChildren(visitor);
         }
     }

     /*
      * @see TextEdit#traverseConsistencyCheck
      */
     int traverseConsistencyCheck(TextEditProcessor processor, IDocument document, List sourceEdits) {
         return super.traverseConsistencyCheck(processor, document, sourceEdits) + 1;
     }

     /*
      * @see TextEdit#performConsistencyCheck
      */
     void performConsistencyCheck(TextEditProcessor processor, IDocument document) throws MalformedTreeException {
         if (fSource == null)
             throw new MalformedTreeException(getParent(), this, TextEditMessages.getString("CopyTargetEdit.no_source")); //$NON-NLS-1$
 if (fSource.getTargetEdit() != this)
             throw new MalformedTreeException(getParent(), this, TextEditMessages.getString("CopyTargetEdit.different_target")); //$NON-NLS-1$
 }

     /*
      * @see TextEdit#performDocumentUpdating
      */
     int performDocumentUpdating(IDocument document) throws BadLocationException {
         String source= fSource.getContent();
         document.replace(getOffset(), getLength(), source);
         fDelta= source.length() - getLength();
         fSource.clearContent();
         return fDelta;
     }

     /*
      * @see TextEdit#deleteChildren
      */
     boolean deleteChildren() {
         return false;
     }
 }

